1. Field of the Invention
The present invention relates to a spindle motor on which an optical disc is put, rotated and operated, and more particularly, to a spindle motor in which a shape of a cap supporting an end of a rotation shaft of a rotor of the spindle motor and a shape of a bearing housing that is closely attached to the cap are improved so that the cap can be prevented from being separated from the bearing housing, the cap can be easily pressed into the bearing housing and can be easily closely attached thereto and leakage of oil can be prevented.
2. Description of the Related Art
A conventional spindle motor illustrated in FIG. 3 is used in the field of spindle motors for rotating an optical disc, which are used in optical disc devices, such as minidiscs (MD), etc. The conventional spindle motor for rotating the optical disc illustrated in FIG. 3 includes a rotor R and a stator S.
The rotor R includes a magnet 101, a rotor yoke 102, a rotation shaft 103, and a turntable 104. The stator S includes a bearing 105, a bearing housing 106 that fixes the bearing 105, a thrust supporter 107 that supports a front end of the rotation shaft 103 in a direction of thrust, an insulated core 109, a winding 108, a substrate 110, and a base plate 112.
When a disc (for example, a MD) is loaded into the turntable 104 of the spindle motor, an optical disc is put on the turntable 104. When the optical disc is ejected from the turntable 104, the optical disc is separated from the turntable 104. In this way, the optical disc can be detached from the turntable 104. Thus, a tool that is used to prevent the rotor R from escaping from the stator S in an axial direction, is needed.
In the conventional spindle motor illustrated in FIG. 3, the rotation shaft 103 of the rotor R is inserted in the bearing 105 of the stator S, and the front end of the rotation shaft 103 is supported by the thrust supporter 107, and the thrust supporter 107 is attached to the bearing housing 106 in a calking manner, and the thrust supporter 107 is coupled to the bearing housing 106 so that the thrust supporter 107 cannot be separated from the bearing housing 106.
However, since the thrust supporter 107 and the bearing housing 106 are attached to each other only in the calking manner, a thrust attracting force of the thrust supporter 107 that acts on the rotation shaft 103 when the spindle motor operates is larger than a press fitting force that is used to attach the thrust supporter 107 to the bearing housing 106 in the calking manner. Thus, the thrust supporter 107 is often separated from the bearing housing 106, and due to a weak close-fixing force of the thrust supporter 107, oil leaks through the bearing 105.
Meanwhile, Korean Patent Laid-open Publication No. 10-2005-0066023 discloses a spindle motor so as to solve a problem that a thrust supporter is separated from a bearing housing. That is, as illustrated in FIG. 4, a bearing housing 20 is installed on a plate 111, and a bearing 30 that supports the rotation shaft 40 is pressed into an inner circumferential surface of the bearing housing 20, and a core 70 is fit to an outer circumferential surface of the bearing housing 20, and a coil 80 is wound around the core 70. A rotor yoke 50 is fixed on the rotation shaft 40 and is apart from the core 70 by a predetermined distance, and a magnet 60 faces the core 70 on an inner circumferential surface of the rotor yoke 50. In addition, a turntable 90 is secured to a top end of the rotation shaft 40, and a thrust supporter 150 is in contact with a bottom end of the rotation shaft 40, and a cap 120 is disposed on the thrust supporter 150 when the thrust supporter 150 is accommodated in the cap 120, and the cap 120 prevents thrust supporter 150 from being separated from the bearing housing 20.
However, in the spindle motor disclosed in Korean Patent Laid-open Publication No. 10-2005-0066023, in which the cap 120 is disposed on the thrust supporter 150 so as to prevent the thrust supporter 150 from being separated from the bearing housing 20, due to a thrust attracting force, the cap 120 may be separated from the bearing housing 20 together with the thrust supporter 150, and due to a weak, close-fixing force of the cap 120, oil may leak through the bearing 30.